Image printing method and apparatus for printing an image based on stored and input image data, including elective printing in an overlapped data area

Abstract

An image printing method and apparatus for combining and printing image data that has already been stored with the image of a read original. The stored image data is printed at a prescribed density, and the image of the original is printed at a density conforming to the gray level thereof. At a portion of a recording medium on which the stored image data and the image of the original will overlap, the stored image data is printed preferentially. Further, the printing of the image and the scanning of the original image for reading the same are executed synchronously.

What is claimed is: 
     
       1. An image printing apparatus for printing an image on a recording medium by driving a recording head in accordance with image data, comprising: storage means for storing first image data;   input means for inputting second image data having multivalued pixel data;   print control means for dividing a print timing for printing at least one pixel corresponding to the image data into a plurality of time intervals for each pixel, assigning a predetermined time interval of the plurality of time intervals for printing a pixel of the first image data, driving the recording head during at least one time interval to form one pixel on the recording medium, and determining a number of time intervals to be assigned for printing a pixel of the second image data in accordance with a tonality of the pixel of the second image data; and   switching means for outputting to said recording head, when first and second image data are assigned to a single pixel to drive the recording head during at least one common time interval, the first image data at the predetermined time interval, and the second image data at time intervals other than the predetermined time interval.   
     
     
       2. The apparatus according to claim 1, further comprising converting means for converting an original image into image data, wherein said second image data is the image data converted by said converting means. 
     
     
       3. The apparatus according to claim 2, further comprising converting means for reading the original image photo-electrically and converting the read image data into said second image data. 
     
     
       4. The apparatus according to claim 3, wherein said print control means operates in synchronism with the reading operation of said converting means. 
     
     
       5. The apparatus according to claim 2, wherein said print control means operates in synchronism with the converting operation of said converting means. 
     
     
       6. The apparatus according to claim 1, wherein said switching means switches said predetermined time interval for each of the pixels of the second image data. 
     
     
       7. The apparatus according to claim 1, wherein said switching means randomly changes said predetermined time interval for each of the pixels of the second image data. 
     
     
       8. The apparatus according to claim 1, wherein said recording head has a plurality of printing elements, and said switching means switches said first and second image data for each printing element and outputs said first or second image data. 
     
     
       9. The apparatus according to claim 1, wherein said image data is half-tone image data, and said print control means prints a multitone image by controlling the number of driving times of said recording head in accordance with a degree of tone of each pixel in said image data. 
     
     
       10. The apparatus according to claim 1, further comprising a plurality of said recording heads, wherein each of said plurality of said recording heads prints a corresponding color image and a multicolored image is printed by said plurality of said recording heads. 
     
     
       11. The apparatus according to claim 1, said recording head has a plurality of outlets to jet ink and jetting means for jetting ink from said outlet. 
     
     
       12. The apparatus according to claim 11, wherein said jetting means creates a change of state in ink, including growth of air bubbles by adding heat energy, and at least one ink drop is jetted by means of the change of status. 
     
     
       13. An image printing apparatus for printing an image on a recording medium by driving a recording head in accordance with image data, said apparatus comprising: memory means for storing first image data;   input means for inputting second image data;   printing means for printing a pixel of a tonal image by driving the recording head during at least one of a plurality of divided time intervals;   selecting means for selecting one of the first image data or the second image data to be printed in the pixel during a time interval in which print timings of the first image data and the second image data are assigned to the same time interval, in synchronism with each of the plurality of time intervals, based on priority information regarding which image data to print; and   print control means for driving said printing means to form an image on the recording medium based on the first image data or the second image data selected by said selecting means to record the pixel.   
     
     
       14. The apparatus according to claim 1, wherein said input means inputs the second image data, which is generated from an original image.